International Research Gives Neuroscientists Better Feeling about Sense of Touch

We often take our sense of touch for granted. Even in neuroscience, scientists do not know much about how it works. However, in a recent study a group of researchers including Carnegie Mellon University’s Alison Barth, have tried to delve deeper into this crucial sensation. The research was published recently in an issue of Neuron. The researchers in this study have linked a group of neurons to a specific type of somatosensation. This finding can open the door for a heightened understanding about our sense of touch.

Carnegie Mellon has been a leader in the study of brain and behavior for more than 50 years. It is the birthplace of artificial intelligence and cognitive psychology. Today, it is building on its strengths in biology, computer science, psychology, statistics and engineering. The result of which is it's recently launched global initiative BrainHubSM. It focuses on how the structure and activity of the brain give rise to complex behaviors.

Barth, a professor of biological sciences and a member of Carnegie Mellon’s BrainHubSM research initiative opined that somatosensation is critical. As humans we can somewhat overcome losing our sense of smell, sight, taste, or hearing. However, if we lose our sense of touch, we will not be able to sit up or walk. In fact, one wouldn’t be able to feel pain or anything else. She added that even though it is such a critical sense, we know the least about it.

As the birthplace of artificial intelligence and cognitive psychology, Carnegie Mellon has been a leader in the study of brain and behavior for more than 50 years. Building on its strengths in biology, computer science, psychology, statistics and engineering, CMU recently launched BrainHubSM, a global initiative that focuses on how the structure and activity of the brain give rise to complex behaviors.

Somatosensation is actually our sense of touch. It occurs in a number of forms, like feeling texture, temperature, pressure, pain or vibration. It is what is responsible for proprioception, which helps us know where we are within our environment; it tells us if our feet are firmly planted on the floor, etc. Scientists have a good knowledge about the molecular receptors that mediate the different types of somatosensation. However, little is known about how it is represented in the brain.

Barth said that we know how information gets transmitted form the skin to the spinal cord when one gets pricked by a pin. What is not known is what happens inside the brain. Since, there are so many activities happening in the brain, everything is a jumble.

In some previous studies, Barth had observed that certain groups of neurons in the brain’s neocortex were more active than others. She used the fos-GFP mouse, a transgenic mouse model to study activity in live neurons. She and her colleagues wanted to find out if these neurons responded specifically to one stimulus or were generally more excitable. In their study, they found that the neurons reacted much more quickly and strongly when a puff of air was directed at the mouse’s whiskers, while other neurons had little or no response.

This showed that have different jobs to do in the cortex. The one they were observing responded when all of the mouse’s whiskers moved at once. It was also found by them that these particular neurons received direct synaptic input from the posteromedial nucleus of the brain’s thalamus. It confirms that the neurons that react to the puff-of-air stimulus have a dedicated, unique sub-network of connections that lets them communicate with one another and amplify the information they are receiving from the stimulus.

Barth said this knowledge have opened up avenues of understanding somatosensory functions. It is hoped that this finding will eventually lead to a work that will identify how somatosensory information is coded, which could be used to incorporate sensory information into brain-machine interfaces. Such a breakthrough could allow robotic limbs and prosthetics to actively sense and receive tactile input.

The research was funded by the Deutsche Forschungsgemeinschaft, the European Research Council, the Alexander von Humboldt Foundation, the European Union and the National Institutes of Health.

References

https://www.cmu.edu/news/stories/archives/2015/january/touch-and-neuroscience.html

https://medicalxpress.com/news/2015-01-international-neuroscientists.html